An n-contact layer, used for a GaN-based semiconductor body, for example, conventionally comprises a titanium layer and a silver layer applied thereto. Such n-contact layers allow good electrical and optical properties to be achieved. However, with such n-contact layers, very thin titanium layers with thicknesses of less than 0.5 nm are needed for good optical properties. These are very difficult to produce and are subject to a number of processing variations.
In addition, although titanium exhibits good electrical contact relative to n-GaN, titanium has comparatively poor reflectivity, such that light emitted by the semiconductor body is disadvantageously absorbed by the titanium layer of the n-contact layer. In contrast, silver is a good reflector for radiation in the visible spectral range, but disadvantageously exhibits unfavorably high contact resistance to n-doped GaN. In addition, titanium and the combination of titanium and silver exhibit different physical properties, which may be disadvantageous for semiconductor chips. For example, titanium is highly reactive and is capable of oxidizing easily, which may lead to a poorly conductive electrical barrier due to the increase in contact resistance.